Welcome to RALF

RALF is a relation-algebraic formula manipulation system and interactive
proof checker. Its meta language is first-order predicate logic in
calculational style, that is the major tools are substitution of equals for
equals, weakening and strengthening. RALF supports this proof style by a
graphical user interface: Theorems are represented as trees and the
subexpression to be transformed can be selected by mouse click. In the first
sections we describe the theory RALF is based on and then how to work with the
system.